24M have set up a pilot manufacturing plant at their HQ at Cambridge, demonstrating not only the cost benefits of the new batteries, but also how they’ve impacted and drastically improved performance and recyclability through their new design.
24M a spin-off company from MIT have developed an advanced manufacturing approach for lithium-ion batteries. The company promises to drastically cut the cost of the most widely used type of rechargeable batteries in the world – whilst at the same time improving their performance and making them more environmentally considerate and easier to recycle.
“We’ve reinvented the process, the existing process for manufacturing lithium-ion batteries has hardly changed in the two decades since the technology was invented, and is inefficient, with more steps and components than are really needed.” says Yet-Ming Chiang, the Kyocera Professor of Ceramics at MIT and a co-founder of 24M.
Chiang developed the process along with W. Craig Carter the POSCO Professor of Materials Science and Engineering based on a “flow battery” platform they developed five years ago whilst running battery company A123.
The new battery design is a hybrid between flow batteries (whereby the electrodes are suspensions of tiny particles carried by a liquid and pumped through various compartments of the battery) and conventional solid ones: in this version while the electrode material does not flow, it is composed of a similar semisolid, colloidal suspension of particles. Chiang and Carter refer to this as a “semisolid battery.”
The reinvention came after Chiang published a paper in the Journal of Power Sources where he analyzed the tradeoffs involved in choosing between solid and flow-type batteries. Almost immediately after publishing the research, Chiang says, “We realized that a better way to make use of this flowable electrode technology was to reinvent the [lithium ion] manufacturing process.”
Current manufacturing methods apply liquid coatings to a roll of backing material, wait for it to dry, and then move onto the next manufacturing step. The new process keeps the electrode material in a liquid state and requires no drying stage at all. Using fewer and thinner electrodes reduces the architecture of the conventional battery, as well as the amount of nonfunctional material in the structure by upto 80%.
Having the electrode in the form of tiny suspended particles instead of consolidated slabs greatly reduces the path length for charged particles as they move through the material. A less tortuous path makes it possible to use thicker electrodes, which in turn simplifies production and lowers cost.
Alongside the new streamlined manufacturing process, Chiang’s system has produced a battery that is both more flexible and resilient. The new formulation allows the batteries to be bent, folded and even penetrated without failing, improving both safety and durability.
So far the company has prototyped 10,000 batteries, which are currently undergoing testing by three independent industrial partners. So far 24M have raised $50million in financing from VC’s and the U.S Department of Energy grant.
Initial focus will be on installing units into the renewable energy markets that currently produce intermittent output, such as wind and solar power. But Chiang says that the technology is also well suited to applications where weight and volume are limited, such as electric vehicles.
By 2020 Chiang envisages that 24M will be able to produce batteries for less than $100 per kilowatt-hour of capacity.